<!DOCTYPE html>
<html>
    <head>
        <script src="vue.js"></script>
    </head>
    <body>
        <div id="app">
            <input type="text" v-focus="true">
        </div>
        <script>
            Vue.directive('focus',{
                inserted (el, binding) {
                    console.log('页面元素插入');
                    console.log(binding);
                    if (binding.value) {
                        el.focus();
                    }
                }
            });

            var vm = new Vue({el:'#app'});
        </script>
    </body>
</html>